Chronic orofacial pain is a relatively common, poorly understood set of conditions that lacks definitive diagnostic methods, prognostic models, or efficacious treatment. Quantitative sensory testing (QST) of the trigeminal nerve has helped elucidate the mechanisms of a subset of these pain conditions. Use of QST has the potential to shed further light on pain etiology and improve the diagnosis and treatment of orofacial pain problems. Recently, the 10 centers of the German Research Network on Neuropathic Pain (DFNS) launched an initiative to standardize a feasible yet comprehensive protocol of QST for specific regions on the external body surface. Funded by the parent grant (1R21 DE0187668-01A1, Drangsholt, PI), we have adapted this protocol for intraoral regions innervated by the trigeminal nerve. We are currently assessing the reliability of these measures in normal controls and patients with idiopathic orofacial pain in the dentoalveolar region. There is also growing evidence that, in addition to dysfunction of the trigeminal system, damage to taste fibers in the chorda tympani branch of the facial nerve may be related to oral pain conditions. Findings of taste dysfunction have been reported both for patients with idiopathic orofacial pain and burning mouth syndrome (BMS). This suggests that inclusion of regional taste testing with intraoral QST may increase the ability of such testing to adequately characterize sensory dysfunction in oral pain conditions. In the parent study, we are testing controls and patients with persistent idiopathic orofacial pain internationally at three universities, on two visits, to measure reliability of the entire QST battery without tongue or taste assessments. We propose to extend the DFNS protocol for intraoral regions to include somatosensory and regional taste testing on the tongue. This extension will allow assessment of the contribution of taste system damage to intraoral pain, and has the potential to improve classification of orofacial pain patients. BMS patients and controls will be tested in the University of Washington Regional Clinical Dental Research Center (RCDRC). The RCDRC is part of the Clinical Research Center Network of the Institute of Translational Health Sciences, based at the University of Washington and supported by a National Institutes of Health Clinical and Translational Science Award. Accomplishing this work will require purchasing additional equipment and hiring an additional 100% effort staff member for the project. A collaborator will be added to the project with expertise in taste assessment. The NEW aims proposed for this competing revision are: 1) Using tongue QST and regional taste tests, measure the test-retest and inter-rater reliability in patients with burning mouth syndrome and controls;2) Determine the initial accuracy of QST/taste measures for differentiating patients with burning mouth syndrome from controls, and 3) Assess the relationship between taste function measured by direct testing, as well as self-reported taste disturbance, and QST pain measures in patients with burning mouth syndrome and controls. The long-term goal is to use QST and taste tools developed through this research to provide evidence-based criteria and methods to improve the differential diagnosis, classification, prognostic prediction and treatment of chronic, persistent, intra-oral pain conditions. PUBLIC HEALTH RELEVANCE: Chronic pain in the face and mouth are relatively common conditions, and often have a devastatingly negative impact on the individual. This research aims to modify nerve testing protocols used on external body surfaces to evaluate pain condition inside the mouth. In addition, we will use methods to evaluate taste function of the tongue. We anticipate that these adapted 'inside the mouth'protocols will aid in the diagnosis and treatment of chronic orofacial pain.